Road Running Energy Supplements: When to Use Gels, Bars, and Chews

Introduction

“Hitting the Wall” is the most feared term among marathon runners. After passing the 30–32 km mark, muscle glycogen is depleted, and runners suddenly feel their legs go weak, their mind becomes foggy, and their pace drops rapidly. A proper energy supplementation strategy is the key weapon to break through this wall. At major Taiwanese events such as the Standard Chartered Taipei Marathon and the Taipei Ultra-marathon, aid stations are limited, so learning to carry and use energy supplements is a required course for advanced runners.

How Glycogen Works

The body’s main energy sources during running:

• Glycogen: Stored in muscles and the liver, providing about 90 minutes of high-intensity exercise
• Fat: Abundant in supply but slower to metabolize, accounting for the majority during low-intensity exercise
• When pace exceeds the lactate threshold (approximately 80% or more of maximum heart rate), the body relies almost entirely on glycogen

For full-marathon runners aiming to maintain a steady pace, carbohydrate supplementation should begin 60–75 minutes into the run, with a recommended intake of 60–90g of carbohydrates per hour.

Comparison of the Three Supplement Types

Using Energy Gels

Energy gels are the primary supplement for marathons, with a liquid texture that is easy to swallow and convenient to carry. Major brands:

• GU Energy: The most common in Taiwan, with a variety of flavors; some contain caffeine (75mg)
• Maurten Gel 100: Low-osmolarity design, touted as “gentlest on the stomach,” suitable for those who experience stomach discomfort with regular gels
• CLIF Shot: Made with organic ingredients; caffeinated versions speed up absorption
• Taiwanese local brands: Some domestic nutrition brands produce energy gels, available at running gear stores

When and how to use:

• Take the first packet 45–60 minutes after the race starts, then one packet every 40–45 minutes thereafter
• Gels must be taken with 150–200ml of plain water to dilute the osmolarity and avoid stomach discomfort
• Never take gels with sports drinks simultaneously (double high-osmolarity beverages are a leading cause of gastrointestinal cramping)
• Caffeinated gels are recommended for the latter half of the race (beyond 20km), making good use of caffeine’s energizing effect

Using Energy Bars

Energy bars are closer to real food, with higher carbohydrate content and generally better gastrointestinal tolerance than gels. They are suitable for:

• Long-duration, low-intensity training runs (at slower paces, the digestive system can still handle solid food)
• Early-stage ultra-marathon fueling (first 40km)
• Pre-race energy top-ups 2–3 hours before the start

Recommended in Taiwan: CLIF BAR series and KIND Bar (natural nut flavors), both available at Taiwanese running gear stores.

Using Energy Chews

Chews fall between gels and bars. Their gummy-candy texture makes them more palatable for many runners, and they can be consumed “in portions”—for example, eating a few every 15 minutes, offering more flexibility than downing an entire gel packet at once.

Special advantages:

• Some varieties contain electrolytes (sodium, potassium), covering both sugar and salt in one go
• In Taiwan’s summer heat, chews are less prone to thinning and leaking than gels
• The psychological act of “chewing” helps alleviate the boredom of long distances

Fueling Strategy for Taiwanese Races

Using the Taipei Marathon as an example (distance 42.195km, aid stations approximately every 5km):

• 0–15km: Warm-up phase; water only, no energy supplementation needed
• 15–30km: Drink water at aid stations every 5km, while supplementing with a gel every 40 minutes
• 30–42km: Entering the “wall danger zone”; if carrying caffeinated gels, use them around the 30km mark
• Recommended to carry throughout: 3–4 gels, or 2 gels + 1 packet of chews

Practical Tips

• Test supplements 2–3 weeks before the race: Try your chosen gel brand during long training runs to find a variety your stomach can tolerate. Never try a new product for the first time on race day
• Store in an easily accessible location: Front pocket of a waist pack, compression shorts pocket, or attached to a race-bib belt
• Track your fueling schedule: Set a 40-minute reminder on your running watch to avoid forgetting to fuel while focused on running

Conclusion

Energy supplements are a strategic resource for the latter half of a marathon. Choosing the right products and taking them at the right times allows you to maintain your rhythm through the “devil’s zone” after 30km. Start practicing your fueling strategy on your next long training run, so that race-day fueling becomes a powerful ally rather than a variable.

Related Reading

• Complete Comparison of Road Running Energy Supplements: Gastrointestinal Tolerance Analysis of Gels, Bars, and Liquid Fuel
• Sports Supplement Buying Guide: Differences Between Energy Gels, Bars, and Electrolytes
• Marathon Aid Station Strategy: When to Drink Water and When to Take Energy Gels
• Energy Supplementation During Exercise: Comparing Gels, Bars, and Real Food